ProMedia 4.1 RMS Rating and Subwoofer Setup

[Dan F]

I don't think you'd find much difference in output between the various 400 Watt specs, but you know what? I recommend buying the 4.1 just because it sounds good, hammers loud, and rattles the pictures. But how to say that with numbers?..?

[Dr Sevrin]

Nor would you find much difference in the output between the 4.1 and the 80 watts RMS VideoLogic Crossfire, which actually goes slightly louder, but that's not really the point.

No doubt the 400 Watts RMS rating is wonderful from a marketing perspective, and in terms of bragging rights as well, but it also begs the question of what exactly you mean by 400 watts (which is in essence one of the two original questions in this thread).

Yes, I did buy the 4.1 for the reasons you mentioned, among others, and I consider them all to be very good reasons for doing so. While I appreciate the recommendation, I'm here for answers to technical questions that you invited from over at 3dss.

With regard to how to say the above with numbers, it would seem that the Klipsch marketing team concluded you do so with an apples to oranges RMS rating.

[Dan F]

...and I'm glad to give the answers.

Since this is a very orange-like system, it's hard to draw direct comparisons.

Thanks for the feedback.

[Dr Sevrin]

I guess Ill take the above as a form of acknowledgement that a power rating of the 4.1 based on nominal speaker impedances, as would be done on a separate hi-fi amplifier by an independent party such as Sound and Vision, would be significantly less than 400 watts.

So lets address the obvious question: Assuming for the moment that a rating based on nominal impedances has not been done (which seems a bit of a stretch IMO), and since this is a voltage limited system (as you state above), what would you estimate the power rating to be using the nominal impedance of 4 ohms for the satellites and 8 ohms (or whatever the nominal impedance is) for the sub? In light of the recent announcement, please also estimate the power rating for the new 5.1 in the same manner.

No, this isnt going to provide the elusive direct comparison, which would involve doing the actual measurements, but it will take us a lot closer to that goal.

One loose end: the question about the rumored change in the 4.1 sub (as compared to the v.2-400) was based on various claims of acoustical differences. Are they identical or different with respect to their acoustics? If they do differ, what was changed?

[Gluegun]

I'm just reviving this old thread....

What is the RMS into 4 and 8 ohms, like Sevrin said??

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"Feh."

[justin_tx_16]

here are basic equations

to find the resistance (ohms)...

R=Voltage/Amps

the resistance on promedia speakers is 4ohms=120V/A, so we can find that 4xA=120, so A=30, ProMedia speakers are at 30 Amps.

Ro find the RMS (root mean squared) You do...

first find the wave form

R(x)= x Squared

now find the function from the last step as an average...

Sigma sub i to the ^n power time X^1 sub i, all of this is divided by n and then square rooted

for continuous (the last one being descrete)

f P(x)x^2 dx divided by f P(x) dx and then square root that

and finally, find the square root of the function from the last step

R(a sub1 + c, a sub 2+c,...) <c+R(a sub 1, a sub 2,..., a sub n) c being the constant

standard deviation is the square root of the mean squared deviation of a signal from a given baseline

this is not easily understood, i understand that

here is a picture which shows another form of the above formulas, a little easier to read

more easily understood equations for this are...

the root mean is found by figuring this...

( 1/T dt x^2(t) )

here you get the RMS average, x is the amplitude of the sine wave, T is the duration of the wave (above equation) n is hte number of samples.

( 1/n Sigma sub i=1..n x sub i ^2 )

thus the science of RMS

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-justin

SoundWise Support

A technical help site created by me and my fellow Klipschers

I am an amateur, if it is professional;

ProMedia help you want email Amy or call her @ 1-888-554-5665 or for an RA# 800-554-7724 ext 5

Klipsch Home Audio help you want, email support@klipsch.com or call @ 1-800-KLIPSCH

RA# Fax Number=317-860-9140 / Parts Department Fax Number=317-860-9150s>

[Gluegun]

*SCREAMS in fear*

AHHHHH!!!! CALCULUS!!! EVIL!!!

*gunshots are fired*

....

Okay, okay, could anyone work this? I would LOVE to know how many continuous watts actually get put out..so as to compare this to, say, Videologic speakers?

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"Feh."

This message has been edited by Gluegun on 04-16-2002 at 10:28 PM

[justin_tx_16]

actually, this is physics more than calculus, though having calculus really helps

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-justin

SoundWise Support

A technical help site created by me and my fellow Klipschers

I am an amateur, if it is professional;

ProMedia help you want email Amy or call her @ 1-888-554-5665 or for an RA# 800-554-7724 ext 5

Klipsch Home Audio help you want, email support@klipsch.com or call @ 1-800-KLIPSCH

RA# Fax Number=317-860-9140 / Parts Department Fax Number=317-860-9150s>

[Talon]

stupid integrals...thought i left you when i passed calc last semester It will follow me to the grave

[justin_tx_16]

quote:

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Originally posted by Talon:

stupid integrals...thought i left you when i passed calc last semester

It will follow me to the grave

---

i am in calc right now, however, i fully agree

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-justin

SoundWise Support

A technical help site created by me and my fellow Klipschers

I am an amateur, if it is professional;

ProMedia help you want email Amy or call her @ 1-888-554-5665 or for an RA# 800-554-7724 ext 5

Klipsch Home Audio help you want, email support@klipsch.com or call @ 1-800-KLIPSCH

RA# Fax Number=317-860-9140 / Parts Department Fax Number=317-860-9150s>